Observation of the decay $B^+ \to \psi(2S) \phi(1020) K^+$ in pp collisions at $\sqrt s =$ 8 TeV

The decay B+→ψ(2S)ϕ(1020)K+ is observed for the first time using data collected from pp collisions at s=8TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.6 fb−1 . The branching fraction of this decay is measured, using the mode B+→ψ(2S)K+ as normalization, to be (4.0±0.4(stat)±0.6(syst)±0.2(B))×10−6 , where the third uncertainty is from the measured branching fraction of the normalization channel.